The primary goal of the proposed research is to develop an economic, versatile microcomputer-based unit analysis system which integrates recent advances in microelectronic technologies (speed, resolution and storage capabilities) to discriminate unit activity on the basis of specific quantifiable criterion. Evaluation and subsequent modification of this system will be based upon the ability of the system to discriminate and analyze the activity of two well-described cell-types, i.e., complex-spike and theta-type cells, within regions CA1 and the dentate gyrus of the dorsal hippocampal formation in the chronically implanted rat. Extracellular recordings will be obtained from these two regions during the vigilance states of still, alert behavior (SAL), slow-wave sleep (SWS) and rapid-eye-movement (REM) sleep utilizing a chronic microdrive assembly. These recordings will be subjected to analysis by the microcomputer-based system for determination of the spontaneous activity of these specific cell- types during the various vigilance states. Such a system may ultimately be used in studies correlating specific unit activity with particular behaviors and/or electrographic patterns (such as the theta rhythm apparent in the EEG during REM sleep). Thus, development of this real-time analysis system will provide researchers with the ability to identify and analyze neuronal activity of the CNS in a more quantitative and standardized manner.